Heart valve disease is a serious problem that involves the malfunction of one or more valves of the heart. The malfunction can manifest itself in a variety of manners. For example, valve stenosis is the calcification or narrowing of a native heart valve. As a result, the native heart valve is not able to completely open and blood flow through the native valve is impeded or restricted. Another example of heart valve disease is valve insufficiency. Valve insufficiency is the failure of a native heart valve to close properly to prevent leaking, or backflow, of blood through the valve.
One method of treating valve disease is to replace the native valve with an artificial or prosthetic heart valve. Prosthetic heart valves include stent-mounted soft tissue heart valves that are delivered using a catheter. For example, the prosthetic heart valve may be mounted on the balloon of the balloon catheter. The balloon catheter is advanced to the native heart valve site. Then the balloon is expanded to release or expand the stent supporting the heart valve into place within the native heart valve. The balloon is then deflated and the balloon catheter withdrawn.
Problems have arisen where the stent supporting the tissue valve is expanded in a non-cylindrical manner, for example, when the ends of the stent flare outwards into a dog-bone shape. The flared ends can negatively influence valve performance or can damage the tissue surrounding the implanted valve.
Accordingly, a need exists for improved prosthetic heart valves and/or balloon catheters that deliver them to reduce or eliminate the flared ends of the valves.